The billionaire is not popular personally with the crowd here. The audience is disproportionately young and libertarian – Trump was booed last year after proposing to fight ISIS with ground forces – and many attendees this year said they plan to vote third party if he is nominated.

In retrospect, though, the convention hosted by the American Conservative Union (ACU) has been a canary in the coal mine for weaknesses in conservatism that are now tearing the movement apart amid Trump’s impending candidacy.

Consider one of its most infamous moments. In 2007, Mitt Romney fired up the crowd for upcoming speaker Ann Coulter, who then used her speech to call Democratic Senator John Edwards a “f—got.”

That scene is instructive now. Romney knew the risks of appearing with Coulter, who famously responded to the 9/11 terror attack with a call to “invade their countries, kill their leaders and convert them to Christianity.” By praising Coulter onstage, Romney lent her credibility and received authenticity in exchange.

Nine years later, Romney delivered an impassioned speech on Thursday rallying Republicans to stop Trump, who is enthusiastically backed by Coulter. But Romney’s message was undermined by his decision in 2012 to accept an endorsement from Trump in person in Las Vegas despite Trump’s race-baiting campaign to prove Obama was secretly born in Kenya. Trump boasted after this week’s speech that the former nominee would have “dropped to his knees” to beg for his backing.

As it turns out, a number of conservatives have criticized CPAC for legitimizing Trump with the mainstream right by giving him prime speaking slots year after year. Trump has donated over $100,000 to the ACU, according to a Politico report this week that quoted a Rubio aide and an anti-Trump super PAC both grumbling how CPAC helped enable Trump.

But the issue is more than just Trump the man. Many of the same tensions that have played out between establishment Republicans, conservative activists, and the extreme fringe over his current platform and rhetoric have also played out in CPAC over the years.

He goes on to chronicle some of the many stories of racist, xenophobic, bigoted, extremist behaviors that have been reported from this gathering and notes:

For a long time it was a running joke among Republicans – and not without some truth – that CPAC was a festival for liberal journalists out to embarrass the GOP, who would breathlessly write up the most incendiary lines from speakers and track down the wackiest figures for interviews. Stephen Glass, the infamous New Republic fabulist, filed a phony story in 1997 about conservative students partying at CPAC. Leftist documentarian Max Blumenthal recorded a short film at the event in 2007 that went viral. It’s still an annual tradition for news cameras to swarm William Temple, the tea partier who dresses in 18th century period costume.

The implication was that there were really two CPACs, only one of which was worth taking seriously. There was the CPAC on the main stage, at which presidential contenders including Ronald Reagan extolled conservatism. Then there was the fringe CPAC, which included cranks who sponsored a booth or sat in for a little-attended panel but were hardly representative of something bigger. The idea someone like Paul Ryan had any connection with, say, the professional pickup artist teaching conservatives how to find right-leaning lovers was ludicrous.

But with Trump roiling the party, the barrier has disappeared. Far from separating two worlds, it’s possible CPAC and hundreds of events sent another message to Republican voters: You should trust these fringe speakers, they’re on the same stage as a presidential candidate.

Today, the fringe speaker is the presidential candidate.

Of course, the difference between the fringe and the main stage speakers to a whole bunch of the GOP coalition wasn't that the main stage speakers didn't say these things. They always did, they just used the dogwhistle.

There is no more dogwhistle. So it's all out in the open and the main stage people are uncomfortable having to defend their bigotry in the open.

But make no mistake, all these mainstream Republicans who were and are screaming about amnesty and "welfare" and anchor babies and "food stamps" and Obamacare are bigots. They just don't come right out like Trump does and say "it's ok to hate Muslims and blacks and Mexicans (well "the bad ones" if you know what I mean.) And it's a-ok for you want America to go back to a time when these people knew their places."

On some practical level the main stage people recognize that old world is gone and that they simply cannot afford to alienate everyone but conservative white people. So they've been trying to keep that view on the down low. Trump has brought it right into the open. But it's always been there.